This invention relates generally to fluid handling and more particularly to a capless medical valve.
Needleless injection ports, installed in an infusion line, allow medical personnel to administer medications to patients occasionally through the already-installed infusion line. To be safe and effective, a needleless injection port must prevent leakage of intravenous fluid out of the port while it is idle, and must absolutely prevent air or other matter from entering the infusion line accidentally. The injection port should not have recesses which could harbor microbes, and it is convenient if contamination can be prevented without requiring a separate cap.
A number of capless medical valves are known, including that shown in U.S. Pat. No. 5,006,114. That valve has a member which can be depressed to open a flowpath when a syringe tip is pushed into the valve body; however, it is necessary to give an irregular surface to either the end of the syringe tip or to the valve plunger. Were both surfaces to be planar, the mating surfaces could work together as a seal, preventing--or at least throttling--flow out of the syringe. Irregularities like the bumps described in the above patent have a disadvantages of more difficult manufacture, and of making surfaces harder to clean. It is not practical to provide special syringes with irregular tip surfaces for just this one use, and it is preferred that the needleless valve have only smooth surfaces, so that it can be cleaned easily by wiping.